1. Field of the Invention
The present invention relates to an absolute rotary encoder operative to measure displacements through the use of flux coupling, and a micrometer including the encoder mounted thereon.
2. Description of the Related Art
A rotary encoder comprises a stat or having transmitting windings and receiving windings arranged thereon, and a rotor having tracks arranged thereon as capable of flux coupling with these windings. Such the encoder includes the absolute type as disclosed in JP-A 10-213407 (FIGS. 2 and 3) and U.S. Pat. No. 3,812,481 (column 5, line 68 to column 6, line 3; column 7, lines 31-35; FIGS. 1 and 2). In particular, the latter discloses a relatively large rotary encoder, which is applicable to control of internal combustion engines. Installation of the stator and the rotor into an enclosure may cause a displacement of the stator or the rotor. In this case, regardless of the size of the absolute rotary encoder, the extent of magnitude of the displacement is almost same. Therefore, downsizing the absolute rotary encoder results in an increase in influence from the displacement and causes a reduction in measurement accuracy.
The present invention has an object to provide an absolute rotary encoder capable of achieving accurate measurements even if it is downsized and a micrometer including the encoder mounted thereon.